This Sept. 20, 2014, file photo shows Florida State defensive coordinator Charles Kelly, left, talking to defensive back Tyler Hunter in the second half of an NCAA college football game against Clemson in Tallahassee, Fla. (AP Photo/Mark Wallheiser, File)

College football’s four-team playoff has altered some of the drama of the regular season.

On one hand, some of the biggest games aren’t necessarily must-wins, since one loss may not end a team’s playoff hopes. Clemson lost in November last year and still went on to win the national title. Ohio State made the playoff despite failing to win its conference.

The tradeoff, of course, is that more teams are in the hunt later in the season — and that can mean more compelling games in more leagues. If a game has conference title implications in a top league, it can also have playoff implications.

That makes it hard to single out just six games to watch over the next three months, but here are a few matchups to circle during the regular season:

Alabama vs. Florida State (Sept. 2)

The top-ranked Crimson Tide and third-ranked Seminoles face off in Atlanta in just the fourth season-opening game involving teams in the top five. No, the loser won’t be out of the playoff race, but its margin for error will be a bit lower. And games like this between two national title contenders are what fans crave for nonconference play. Alabama also started last season with a neutral-site game against a big-name program. The Tide beat Southern California 52-6.

Clemson at Louisville (Sept. 16)

Deshaun Watson and Lamar Jackson put on quite a show in this matchup last season, combining for 601 yards passing and 253 rushing. A couple of late touchdown passes by Watson lifted Clemson to a 42-36 win. Now the Tigers must replace Watson, while Jackson, last year’s Heisman Trophy winner, returns to lead the Cardinals.

Penn State at Ohio State (Oct. 28)

The Nittany Lions upset the Buckeyes 24-21 last year thanks to a blocked field goal return in the fourth quarter. That was enough to keep Ohio State out of the Big Ten title game, but although Penn State won the conference, it was the Buckeyes who went to the playoff. Both teams will have plenty of motivation for this one.

Oklahoma at Oklahoma State (Nov. 4)

In each of the past two seasons, Oklahoma won this matchup in the regular-season finale with the Big 12 title on the line. The Sooners and Cowboys will play earlier this year, and the Big 12 is bringing back its conference title game — but that won’t take too much of the luster off Bedlam. Quarterback Baker Mayfield is back for Oklahoma, but coach Bob Stoops isn’t , and that might give Oklahoma State an opening this time.

Washington at Stanford (Nov. 10)

Washington’s 44-6 win over the Cardinal last September made it clear that Chris Petersen’s Huskies were for real. They ended up winning the Pac-12 title and advancing to play Alabama in the national semifinals. Stanford has to replace record-setting running back Christian McCaffrey but will have home-field advantage against Washington on a Friday night in November. If the Huskies can get past Colorado on Sept. 23, they could enter the Stanford game unbeaten.

Ohio State at Michigan (Nov. 25)

The Buckeyes prevailed in a double-overtime thriller last year for their 12th victory in the past 13 meetings against their biggest rivals. Jim Harbaugh has only one returning starter on defense, but the Wolverines get Ohio State at home this year.